Observation VS Experiment

Observation is simple, indefatigable, industrious, upright, without any preconceived opinion. Experiment is artificial, impatient, busy, digressive; passionate, unreliable. We see every day one experiment after another, the second outweighing the impression gained from the first, both, often enough, carried out by men who are neither much distinguished for their spirit, nor for carrying with them the truth of personality and self denial. Nothing is easier than to make a series of so-called interesting experiments. Nature can only in some way be forced, and in her distress, she will give her suffering answer. Nothing is more difficult than to explain it, nothing is more difficult than a valid physiological experiment. We consider as the first task of current physiology to point at it and comprehend it.

Observation sounds peaceful, experimentation sounds distressing.